3D TV is here to stay. The technology has come and gone in the past but, now that it's made it into our homes, it's there for good. That's not the end of the story though. There's still a great debate raging as to what form that 3D is going to take. It's all about the glasses and everyone's talking about active shutter 3D vs passive technology, but which is best? Passive 3D is what you're used to seeing in the cinema but does that give it the advantage over the rival system?

"The experience of 3D in the cinema is very different than 3D at home," Panasonic UK's product specialist for consumer products, Steve Lucas, told us when we settled down for a chat about three-dimensional TV.

"It comes down to quality. If you want to experience the same quality that you get at the cinema then the only option is active shutter. 3D is similar to going to the cinema in that it tends to be used for event viewing, so it's a considered decision. With a passive system, it's easy just to put the glasses on without having to make a concious decision to do that, but for an event like a big sports match or a movie, then an active shutter system offers the best quality."

If 3D viewing is considered to be event-viewing, then doesn't it belong in the cinema anyway? Panasonic thinks not, and has been one of the leading forces in the 3D TV revolution since day one and has developed an active shutter 3D system. In a nutshell, there are two types of 3D currently available on TVs for the home - active shutter, as offered by several manufacturers including Panasonic, Sony, LG and Samsung and passive technology, which is only available on panels from LG.

An active 3D system flashes the images for the right and left eyes with each alternate the frame that the TV produces. As a result it requires glasses with LCD lenses that alternately open and shut to display a different image to each eye at a time. They have to sync with the TV's image via infra-red signals from the set and they're powered by a small built-in battery, which makes them bulkier than those used with the rival system.

Passive, on the other hand, is all about polarized 3D glasses, which are both lighter and inexpensive, and they create the illusion of a 3D image by restricting the amount of light that reaches each eye. This means that each eye sees a different image, but at the same time, unlike the shutter system used by the more expensive glasses.

So, why did Panasonic decide to go with active technology, rather than passive? Lucas tells us:

"We believe that our active shutter system delivers the best 3D quality possible. Panasonic has been at the forefront of 3D ever since making the proposal to the BDA [Blu-ray Disc Association] to adopt the frame sequential system and having the infrastructre in place in our Hollywood lab to author the films as well has helped us to develop the software and understand what makes good 3D."

One of the main criticisms that's directed at active shutter 3D systems is the use of larger and more expensive glasses, compared to the cheap, lightweight glasses ones by passive screens. Is this a barrier for consumers? Panasonic's Lucas tells us that it's all a matter of quality:

"There will always be the type of home cinema buff who wants the ultimate viewing experience and active shutter system is the only technlogy that can offer that at the moment. It's right to have the choice available so that they can step into 3D at a level that suits their pocket. But, to have the best picture quality does require the active glasses which have a lot of technology in them. There's currently no other option for getting full HD to each eye".

Lucas is referring to the fact that only active 3D systems transmit a full, 1080p image to each eye, which isn't the case with passive polarized technology. The full HD image on a passive screen is split between the two eyes meaning that the resulting effect is only at half the resolution. While videophiles are unlikely to be unhappy with anything less than 1080p, it's debatable whether it's actually a neccesity for 3D watching.

At around £100 each pair, the price of the active shutter glasses is also likely to put off some punters. If you've got a family of four, then that's £400 spent before you've even factored in the price of the TV and some 3D content to watch on it. And if the glasses break (not unlikely if you got young kids or clumsy teenagers), then they're not cheap to replace. In contrast, extra pairs of passive specs can be picked up for around £20 or even 'acquired' from your local cinema - not that we condone petty theft. Panasonic's Lucas agrees that price is certainly an issue.

"3D does have a premium on the cost of the product, so it's a considered purchase for somebody looking to change their TV at the moment. However, with the rate at which 3D is growing, consumers really have to consider whether they want to jump in with 3D at this stage so that they're not left out in the marketplace. If you have a TV that's not 3D-compatible at this stage then you might live to regret that decision three of four years down the line."

Another common complaint about the active glasses is that they take a while to sync with the screen, so the 3D effect isn't instant. Lucas tells us that, this may be the case but you simply need to allow time for the specs to sync and then for your eyes to adjust, which is why it's important to get a demo from a retailer who knows what they're doing.

"The way that we demonstrate the technology is to stand the viewer in front of the display and explain what they're seeing and the effect they're going to get. It's only about 20-30 seconds before the customer has adjusted. Within three or four minutes of watching, they quickly become engrossed in the scene. You do have to give the customer time to experience that, so it really needs to be demonstrated in-store with the shop staff giving the customer enough time to adjust."

This may be a stumbling block for those who are used to settling down in their cinema seat, armed with popcorn and boiled sweets, popping their polarized glasses on and being able to see the 3D image instantaneously. Does that mean that there's still a place for passive technology in the home 3D world? "Absolutely, yes", says Lucas.

"There is a compromise on quality but it's down to the perception of the viewer and it's good that there's a choice for the customer. The passive displays aren't much cheaper than the active displays at the moment, in fact they're somtimes more expensive. I can understand why the passive technology has been adopted for pubs and clubs and public areas. You really can't have a £100 pair of glasses in the pub where they could get broken or stolen. But, for home use, an active display is best."

Another common concern over 3D is that it won't work if you wear prescription glasses. Lucas downplays this issue, stating that: "Most people that wear glasses can still see the 3D effect by wearing the 3D specs over their own. There's a small percentage of the population that can't see the 3D effect, and for that type of customer, they won't be able to benefit. In the same way that there's a small percentage who are colour blind. It's only a very small number, so it's not a big concern for manufacturers".

It may not be a big concern for manufacturers, but if you do wear glasses then it's even more important that you try 3D out before you buy anything. If you think that the shutter glasses are uncomfortable, then just try wearing them on top of your normal specs - an issue which Lucas seems to ignore.

Another major concern with 3D is crosstalk inteference. This is a sort of ghosting effect that tends to show up round small, bright or background images. This can make the picture look unfocused (a bit like looking at a 3D image without any special specs), and can also lead to tired eyes. Is this a problem that Panasonic has encountered?

"Crosstalk is the big enemy of a good 3D experience and one of the reasons that we've been very happy with the quality of our 3D, as our plasmas display very little, if any, crosstalk - a fact that's been pointed out many times by reviewers.

"At this stage, this is where plasma has the advantage. Crosstalk is there becuase the left eye image is still on the screen when the right eye image is being displayed and that's down to the response speed of the panel. Crosstalk is greatly reduced on plasma and we've added extra circuitry both into the TVs and into the glasses to help reduce it even further. Crosstalk does have to be addressed within the LCD envinronment and manufacturers will be looking at doing that".

We also quizzed Panaosonic's Lucas on what he thinks is the best 3D content that's currently available and he highlighted the merits of James Cameron's Avatar, which was encoded and authored at Panasonic's Hollywood Blu-ray lab. It may be an answer that you'd expect from a Panasonic employee, but it has to be said that the 3D effects on Avatar do look very impressive indeed (if only the same could be said for the plot).

Lucas also went on to tell us that, although football has been used as one of the big selling points for 3D, it's actually not the best sport to watch in three dimensions.

"Football can look okay in certain shots, but you tend to get a lot of long shots and that's where 3D doesn't add a great deal. However, rugby does come across very well becuase of the close-up action and golf also looks incredible in 3D. The undulations of the green in particular, really come across well.

"3D can really be used for everything, whether that's arts, natural history or documentaries, as long as it's shot correctly - and that's where some of the broadcasters and production companies will need to re-learn what they know about shooting in two dimensions."

Although it's true that there is an increasing amount of 3D content emerging all the time, there's still only a handful of 3D Blu-ray discs and the programmes and films that are shown by Sky 3D are on heavy rotation, so there's a lot of repetition. Take a look at what it's like to live with 3D if you don't believe us.

If you can't wait to get 3D into your home then this might not be a concern, but it's certainly worth remembering if you're expecting to see something new in 3D on your TV every day.

So, what of the future? What can we expect to see next in the 3D world?

"3D is not a flash in the pan or just a gimmick," ensures Lucas. "There will be big gains in 3D in 2011. A lot of manufacturers will be releasing 3D-based products this year and we'll also see more content from the broadcasters, film companies and games manufacturers.

"A lot of manufacturers will be considering introducing 3D compatibility into the majority of their new models from now on. It won't happen straight away - but it's likely that we'll see 3D becoming a standard built-in option in the same way that HD has, within the next year or two, beginning with top-tier TV models and filtering down."

And what about the Holy Grail of 3D - glasses-free viewing. Will that feature in Panasonic's plans for the future?

"Ultimately, that will be the ideal situation, but it's many, many years away from the prototype displays that I've seen so far. The limitations are such that it really doesn't suit the home viewing environment at the moment, as only a very small number of users can view the screen at any one time. The viewing angle is just so small. We'll see glassesless displays used on very small screens on mobile devices, but to scale that up to a large screen TV for the home is a long way off."

And finally, what would Steve Lucas say to all the 3D skeptics out there?

"Try 3D for yourself. Make sure you've looking at some good content, the kind of thing that you'd want to watch in 3D, and give yourself the opportunity to adjust. 3D isn't going to be for everyone, but it's here to stay."

Do you have a 3D TV at home? Are you planning to invest in one soon? Active or passive? Let us know in the comments box below.